Messages in this thread Patch in this message | | | Date | Fri, 19 May 2006 18:16:44 -0700 | From | Zachary Amsden <> | Subject | Re: [PATCH] Gerd Hoffman's move-vsyscall-into-user-address-range patch |
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Andrew Morton wrote: > Ingo Molnar <mingo@elte.hu> wrote: > >> * Andrew Morton <akpm@osdl.org> wrote: >> >> >>> Rusty Russell <rusty@rustcorp.com.au> wrote: >>> >>>> Name: Move vsyscall page out of fixmap into normal vma as per mmap >>>> >>> This causes mysterious hangs when starting init. >>> >>> Distro is RH FC1, running SysVinit-2.85-5. >>> >>> dmesg, sysrq-T and .config are at >>> http://www.zip.com.au/~akpm/linux/patches/stuff/log-vmm - nothing leaps >>> out. >>> >>> This is the second time recently when a patch has caused this machine >>> to oddly hang in init. It's possible that there's a bug of some form >>> in that version of init that we'll need to know about and take care of >>> in some fashion. >>> >> FC1 is like really ancient. I think there was a glibc bug that caused >> vsyscall related init hangs like that. To nevertheless let people run >> their old stuff there's a vdso=0 boot option in exec-shield. >> >> > > Well that patch took a machine from working to non-working. Pretty serious > stuff. We should get to the bottom of the problem so we can assess the > risk and impact, no?
An easy test for culpability of kernel vs. init would be to back out all patches and recompile the kernel with vsyscall moved down by 4 megs.
Index: linux-2.6.17-rc/include/asm-i386/fixmap.h =================================================================== --- linux-2.6.17-rc.orig/include/asm-i386/fixmap.h 2006-03-19 21:53:29.000000000 -0800 +++ linux-2.6.17-rc/include/asm-i386/fixmap.h 2006-05-19 18:16:00.000000000 -0700 @@ -20,7 +20,7 @@ * Leave one empty page between vmalloc'ed areas and * the start of the fixmap. */ -#define __FIXADDR_TOP 0xfffff000 +#define __FIXADDR_TOP 0xffbff000 #ifndef __ASSEMBLY__ #include <linux/kernel.h> | |